Enums are now fully implemented for Typescript, Swift, Kotlin, and C#

Python needs a little bit more for full implementation, which will be completed in #242

* Added enum generation for all languages
* Enums are not overwritten and are automatically renamed if the values for the enum vary from another enum of the same name

* Miscellaneous
- replacing `x-looker-values` with `enum` in converted OA spec
- putting license statement into generated files using the `LICENSE` file contents in the package folder
- made `commentHeader` a little smarter